Ratchet-type torque wrench



Aug. 17, 1954 F. w. LIVERMONT RATcHET-TYPE TORQUE WRENCH sheets-sheet 1 Filed April 12, 1952 5 M W N NV Wl e W v W W Q .S .../N l Q ow m.

Allg- 17 1954 F. w. LlvERMoNT RATCHET-TYPE TORQUE WRENCH 3 Sheets-Sheet 2 Filed April l2, 1952 NM Wm m fm m W e 3 Sheets-Sheet 3 Filed April' l2, 1952 INVENTOR.

will

Patented Aug. 17, 1954 UNITED STATE TENT OFFICE-f RATCHETJIYPE; TORQUE WRENCH Frank W. Livermont, Duarte, Calif. ApplicationApril 12, 1952, SerialNo. 2813973 with a head formed, integrally with Va handle andhave a ratchet wheel mounted to turn on the head. A springurged pawl.k allows the ratchet wheel to turn only in one direction.

It is` the. principal object of my invention.k to provide improved torqueeindicating means for wrenches of this type.

It is another object of my invention to provide a torque wrench of this 'type which provides both a visual and audible indicationvwhen the applied torque reaches a predetermined value.

Another object is to provide a device of this type having rugged` and dependable operating parts which are not apt to get out of order and which provide a reliable and accurate signal when. the applied torque reaches the desired value;

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

Figure 1 is a plan view showing a preferred embodiment of my invention.

Figure 2 is a sectional. elevation` taken Substantially on the lineii--Zl as shown inlFigure` 1. Figure 3 is an enlarged fragmental plan View partly in section.

Figure 41 is aplan View of the underside of the` wrench head.

Figure 5 is a. plan View ofthe upper. side of the wrench head. showing" the position of thev parts during application` of; torque below the desired value.

Figure 6 is a View similar to Figure 5 showing theposition of the parts after the torque has reachedY the predetermined magnitude.

Figure 7 is a view similar to Figure 6 showing thepawl shifted to permit the wrench to be used in; a counterclock-wise direction.`

Figure 8 isa detailed perspective view showing parts ofthe pivoted slide block.

Figure 9 is a perspective view showing the guided slide block.

Figure 10 is an exploded view showing the manner of assembly of the various parts` atthe head end of the wrench.

Figure 11 is asectional view` on-,anv enlarged scale showing the action of the pivotedv slide block inits slot.

Referring to the drawings, the wrench geneerallyv designated. Ill; includes a handle II. and

anfintegral' bifurca-ted head2 I2; Therheadi I2in.-

member I5 has agcylindrical portion I6 mounted.

for rotation in the cylindrical bore I l in -thecheek plate` I4. The driver member- I5,v also has anon circular portion iil which nts withinv the nonchl cular bore i5! of the ratchet wheel20. Theratchet wheel 26 is received within the space between the cheekv plates. I3 and III andE turnsv with the- 4 driver member I5. An annular ring2-I Ais received on the centralv cylindrical` projection 22. of the driver member I6 and isk clamped against thez annular shoulder 2.32 by means ofA the washer 211I and screw element 25. The ring. 2l isreceived, within the-cylindricalbore 26 in thecheek` plate; i3. The bores Il' and 26 are aligned and are of the same diameter so that thesquarefprojectng portion 2'! of the driver member I5; may be assembled to project fromeither cheek plate asdef. sired.

The ratchet wheel il is provided`r with the usual ratchet teeth. 28, on its periphery, and: al pawl 29 is provided with. a pairof abutmentsga and 3| for selectiveengagement withtheratchet teeth 28. The pawl 261s carriedon a pivot pin.

32, and thispin connects the pawl 29 tothe pare.

allel flanges 33 and 34 of they carrier generally designated 35. The carrieris: provided, wit-ha;-

tubular stem ewhichprojectsinto anaxialbQre- A Spring. 33. acts` 3l provided on the handle Il. to urge a ball 39 into engagement with, either of the surfaces 40, or 4I on thefpawl.v 2.9.` Whenv the ball.V 3,6 engages the surface` 46. as shown. Figure 3, the abutmentv 3J-isinl1osition.to= enf..

gage the teeth 28 ofthe ratchetr wheel 2.0. Ac-

cordingly, the paws/1,29. permits the` ratchet. wheel.

to turn ina clockwise direction as. Viewedjin Fig.-`

ofthe4 ratchet wheel. When the abutmentV 31;" is swung into teeth-engaging positionthe ballg3g9j engages the surface 41 ofthe pau/129 andthe ratchet wheel 261 ispermitted to turncounter clockwise butl not clockwise as viewed in Figure.

In accordance With, my invention. theY carrier ure 3 butv preventsl a counterclockwise rotation,

35- is guided for movement longitudinally Qithe A plunger 43::

the bore 49 and at one end engages the sleeve 48 and at the other end engages the enlarged end 59 on the rod 5l. The forward end 52 of the rod 5l is slidably received within the bore 53 of the sleeve 49. A set screw 54 is threaded into the outer end of the bore 49 and serves to compress the spring 42. The set screw 54 may be provided with the usual noncircular socket 55 so that it may be turned by means of a wrench (not shown) insertable into the socket.

The pivot pin 32 which connects the pawl 29 to the carrier 35 also passes through aperture 55 on the pivoted slide block 51 and through aperture 58 on the guided slide block 59. The pin 32 is provided with an integral head 50 on one end and is provided on the other end with a removable retaining screw 6l. The slide block 51 is received within a slot 52 provided in the cheek plate i3 while the slide block 59 is mounted within a slot 63 provided in the cheek plate I4. Both slide blocks 51 and 59 move within their respective slots when the carrier 35 moves longitudinally against the action of the spring 42. The slots 62 and 63 are substantially duplicates in order that each may receive either of the slide blocks 51 or `59.

The slide block 59 is guided for longitudinal movement within the slot 53 but does not pivot with respect to the cheek plate I4. The slide block 51, however, slidably nts the slot 52 only at its narrowed forward end 64. The remainder of the length of the slide block 51 has considerable clearance with the sides of the slot 52. The result is that the slide block 51 may pivot about the pin 32 as it moves longitudinally in the slot 62.

As clearly shown in Figure 8 the slide block 51 is provided with a semi-circular projection 55 having a central aperture E5. A lug E1 is provided with a recess 68 to receive the projection 65 and is also provided with aligned apertures 59. A pivot pin 10 extending through the apertures 69 and 66 pivotally connects the lug 61 to the slide block 51. The proportions of the parts are such that the lug 61 may have limited pivotal motion with respect to the slide block 51. The over-all width of the lug 61 is such that it may be slidably received Within the slot 62. The slots 62 and 63 are both provided with enlargements 1l at one end.

In operation the parts may be assembled as shown in Figure 2. The set screw 54 is turned to produce the necessary force in the spring 42. The squared portion 21 of the driver is engaged with a socket to be turned. The pawl 29 is swung manually so that the turning force applied to the Work may be right-hand or left-hand as desired. Assuming that the work is to be turned in a clockwise direction as viewed in Figure 3, the pawl 29 is moved to bring the abutment 3G into engagement with the ratchet teeth 28. When the handle Il is turned clockwise as viewed in Figure 5 a force is exerted by the ratchet wheel 2D against the pawl 29 and against the pin 32. This force causes the end 12 of the lug 51 to engage the surface 13 of the slot 62 and also causes the slide blocks 51 and 59 to move longitudinally of the handle against the action of the spring 42 acting through plunger 43 and carrier 35. As the torque applied to the handle H increases, the slide blocks 51 and 59 continue to move longitudinally away from the axis of the ratchet wheel 20. During this sliding movement of the block 51 the lug 61 assumes the position shown in 4 Figure 5 because of the frictional drag of its end surface 12 on the surface 13 of the slot 52.

When the end surface 12 on the lug G1 eventually rounds the corner 14 at the end of the slot surface 13 the slide block 51 suddenly moves laterally, pivoting about the pin 32 and bringing the side of the block 51 into engagement with the surface 13. This action results in reversing the pivotal position of the lug B1 with respect to the slide block 51 and the parts take the position shown in Figures 6 and ll. An audible sound in the form of a sharp metallic click is produced when the lug 61 rounds the corner 14. This sudden change in position of the parts 51 and 51 also sends a shock wave down the handle H which is readily detected by the hand of the user. This change in position of the parts also provides a visual indication to the user. These various signals are given simultaneously and the user promptly discontinues the application of torque to the handle l I. The set screw 54 may be turned to produce any desired torque value Within the range of operation of the tool. The initial setting may be determined by a torque-measuring device, or in any other desired manner. Once set the torque wrench will produce the signals whenever the predetermined torque value is reached, and within very close limits.

When it is desired to use the tool in a counterclockwise direction the pawl 29 is swung to the position shown in Figure 7. When the handle ll is turned in a counterclockwise direction the surface 15 on the lug 61 rides on the surface 15 of the slot 52. When the predetermined torque value is reached the end surface 15 rounds the corner 11 and the slide block 51 pivots about the pin 32 to engage the surface 16. At the same time the lug G1 pivots with respect to the block 51. This action produces the same signals above described and the user of the wrench is thus notified that the desired torque has been applied.

The sides of the slots 62 and 53 are hardened and the slide blocks 51 and 59, as well as the lug 61, are likewise hardened to minimize wear at the points where sliding action occurs. The corners 14 and 11 are subjected to the greatest amount of wear. When these corners have been worn down the parts may be assembled with the slide block 51 in the groove 63 and the slide block 59 in the groove 62. In this way the service life of the tool is considerably extended.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

l. In a ratchet-type torque wrench, the combination of: a handle having a head at one end, a ratchet wheel mounted for rotation on the head, a pawl cooperating with the ratchet wheel to prevent turning motion thereof in one direction, a carrier mounted for movement longitudinally of the handle, a pivot pin connecting the pawl to the carrier, resilient means mounted on the handle to resist movement of the carrier in a direction away from the ratchet wheel, and signal means operative upon predetermined travel of the carrier.

2. In a ratchet-type torque wrench, the combination of a handle having a head formed integrally therewith, a ratchet wheel mounted for rotation on the head, a pawl cooperating with the ratchet wheel to prevent turning motion thereof in one direction, a carrier mounted for movement longitudinally of the handle, a pivot piil. connecting the pawllfto the carrier, aspring withinftheliandle resisting movementfof the carrierI away4 from the-l ratchetn wheel, and.` signal. means operativeV upon predetermined.longitudinal.

movementofI the carrier..

3.-. aratchet-type torque-wrench, the combinationloff: a handle-having ahead at one end, al ratchet wheel mounted` for. rotation. on the head1, a: pawl. cooperating; with the ratchet. wheel toi-prevent turning motion thereof in one direction; a carrier mounted` for. movement. longitudinallyfof.: the handle, a pivot pin connecting.

onesgeiid,A a ratchet wheelmounted for. rotation ony thefhead, a1 pavvl havingspaced abutmentseach cooperable with the ratchet. wheelv to prevent turning motiony thereofiin one direction, a. carrierr mounted forA movement longitudinally of the handle,. a. pivot pin connecting. the pawl to the.

carrier, the pawl. being shiftable about the pivot pinl tir-bring. either abutmentv into operative ensagement with the ratchet wheel, resilient means mounted on the handleto.. resist movement of the carrier` away from the: ratchet Wheel, and signal meansoperative upon predetermined.longitudinal movement of the. carrier.

5. In a ratchet-type torque wrench, the combination. of: a. handle having a head at one end, a ratchet wheel mounted for rotation on the head, apawl cooperating with the ratchet wheel to prevent turning motion thereof in one direction, aL carrier mounted forl movement longitudinall'y of the'handle, apivot' pin connecting the pawl-'to-the carrier, resilient means mounted on thehandletoresist movement of the carrier in a direction away from the ratchet wheel, and signal means including an element pivotally connected to said pin, the element being guided for movement on the head and having a portion thereof" movable laterally upon predetermined travel of the carrier.

6. In a torque wrench the combination of: a handle having a head at one end, Work-engaging means on the head, a carrier mounted for movement longitudinally of the handle, means operatively interposed between the Work-engaging means and the carrier to cause longitudinal movement of the carrier upon application of torque by the handle to the work-engaging means, resilient means mounted on the handle to resist movement of the carrier, and signal means including a guide means terminating in a laterally offset portion, an element so connected to said carrier as to bear laterally against said guide means and slide therein as said carrier is moved in opposition to said resilient means, and thereby move forcibly into said laterally offset portion upon predetermined travel of said carrier.

7. In a torque wrench the combination of: a handle having a head at one end, work-engaging means on the head, a carrier mounted for movement longitudinally of the handle, means operatively interposed between the Work-engaging means and the carrier to cause longitudinal movement of the carrier upon application of torque by the handle to the work-engaging means, resilient means mounted on the handle to resist assegna movement off'the. carrier, signalI meansrV including a. guide means. terminating in a laterally` oiIsetv portion', arr element: so.: connected toV said. carrier;V as .tov bear laterally against said, guide meansangd,l

slide thereinV as saidcarrierzis movedfin. opposition tosai'dlresilient meansgand thereby move forcibly into. said'. laterally` offsetportion upon predeter-l mined travel'r of said. carrier.

8. Iny a. torque wrench the combination o f.: a.

along: said slot, they elementv havingv a portion.

thereof movable laterally upon predetermined travelin the slot.

9; In a torque wrench the combination of.; a..

handle. having a head," atA one end, the. headhaving walls defining a slot extending` longitudinally of thek handle, work-engaging means. on the head, a carrier mounted for movementv longitudinally. of the handle, means operatively interposed between theworkengaging means and the carrier to cause. longitudinal' movement. of the. carrier upon appli:-` cation oftorque by the handle to the work-engaging means, resilient means mountedonthe handle to resist movement of the carrier, signal means` including a slide block movable in said slot and. pivotally. connected to the carrier, a lug pivotally connected to one end' of the slide block, the lug sl'idably engaging a Wall' of the slot and movable-- laterally upon predetermined travel. along said slot.

10. In a torque wrench the combination of a:

handle having a head at one end, the head hav;-

ing walls defining a slot extending longitudinally of' the handle, the slot having a shoulder at one end, Work-engaging means on the head, a` carrier mounted for movement longitudinally of the handle, means operatively interposed between the work-engaging means and the carrier to cause longitudinal movement of the carrier upon application of torque by the handle to the work-engaging means, resilient means mounted on the handle to resist movement of the carrier, signal means including a slide block movable in said slot and pivotally connected to the carrier, a lug pivotally connected to one end of the slide block, the lug slidably engaging a wall of the slot and movable laterally upon traveling past said shoulder.

11. In a torque wrench the combination of: a handle having a head at one end, the head having walls defining a slot extending longitudinally of the handle, the slot having an offset recess at one end, work-engaging means on the head, a carrier mounted for movement longitudinally of the handle, means operatively interposed between the work-engaging means and the carrier to cause longitudinal movement of the carrier upon application of torque by the handle to the work-engaging means, resilient means mounted on the handle to resist movement of the carrier, and signal means including a slide block movable in said slot and pivotally connected to the carrier a lug on the slide block slidably engaging a wall of the slot and movable laterally into the offset recess upon predetermined travel of the carrier.

v12. In a ratchet-type torque wrench, the combination of: a handle having a head at one end, a ratchet wheel mounted for rotation on the head, a pawl cooperating with the ratchet wheel to prevent turning motion thereof in one direction, a carrier mounted for movement longitudinally of the handle, a pivot pin connecting the pawl to the carrier, resilient means on the handle resisting movement of the carrier away from the ratchet wheel, the head having walls defining a slot therein extending longitudinally of the handle, the slot having an offset recess at one end, a slide block mounted for movement in the slot and pivotally connected to said pin, a lug pivotally connected to the slide block at one end, the slug slidably engaging a Wall of the slot and movable laterally into the oiset recess upon predetermined travel of the carrier.

13. In a reversible ratchet-type torque wrench, the combination of: a handle having a head at one end, a ratchet Wheel mounted ior rotation on the head, a pawl having spaced abutments each cooperable with the ratchet Wheel to prevent turning motion thereof in one direction, a carrier mounted for movement longitudinally of the handle, a pivot pin connecting the pawl to the carrier, the pawl being shitable about the pivot pin to bring either abutment into operative engagement with the ratchet wheel, resilient means on the handle resisting movement of the carrier away from the ratchet wheel, the head having walls deiining a slot therein, the slot having offset recesses at one end, a slide block mounted for movement in the slot and pivotally connected to said pin, a lug on the slide block and extending laterally beyond the side edges of the slide block to slidably engage either wall of said slot, the slide block turning about the pivot pin to engage a wall of the slot when the lug enters one of the offset recesses.

14. In a ratchet-type torque wrench, the combination of: a handle having a head at one end, a ratchet Wheel mounted for rotation on the head, a pawl cooperating with the ratchet wheel to prevent turning motion thereof in one direction, a carrier mounted for movement longitudinally of the handle, a pivot pin connecting the pawl t0 8.. the carrier, the pawl applying a force to the pin in a direction at an angle to the direction of movement of the carrier, resilient means resisting movement of the carrier away from the ratchet wheel, the head having walls defining a slot therein and provided with a shoulder, a slide block mounted for movement in the slot and pivotally connected to said pin, a lug on the slide block and extending laterally beyond the side vedges of the slide block, the lug slidably engaging a wall of said slot, the slide block turning about the pivot pin by the action of said force when the lug travels beyond the said shoulder.

15. In a ratchet-type torque wrench, the combination of: a handle having a head formed integrally therewith, a ratchet wheel mounted for rotation on the head, a pawl cooperating with the ratchet Wheel to prevent turning motion thereof in one direction, a carrier mounted for movement longitudinally of the handle, a pivot pin connecting the pawl to the carrier, a spring Within the handle resisting movement of the carrier away from the ratchet wheel, means for adjusting the force of the spring, the head having walls deiining a slot therein and provided with a shoulder, a slide block mounted for movement in the slot and pivotally connected to said pin, a lug pivotally connected to the slide block and extending laterally beyond a side edge of the slide block, the lug slidably engaging a wall of said slot, the slide block turning about the pivot pin to engage the said wall of the slot When the lug travels beyond the said shoulder.

1References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,860,871 Pouliot May 31, 1931 2,179,855 Latimer Nov. 14, 1939 2,300,652 Cooney Nov. 3, 1942 2,365,486 Morris Dec, 19, 1944 2,427,153 Mossberg Sept. 9, 1947 FOREIGN PATENTS Number Country Date 116,761 Sweden July 2, 1946 

